A conventional data storage system divides the available storage on each physical storage disk into a data section and metadata section which is separate from the data section. The data section on each storage disk is divided into a range of 1 megabyte (MB) slices to hold regular data. The metadata section on each storage disk describes the current state of each 1 MB slice in the data section of that storage disk.
For example, when a logical unit of storage (LUN) is bound, the metadata section of each storage disk is marked to indicate that each 1 MB slice of the LUN must be initialized to zero. Next, a low priority service is started to initialize the marked 1 MB slices to zero and the data storage system begins performing read and write operations on behalf of one or more host computers. Then, for incoming read and write operations, the data storage system checks (i.e., reads) the metadata sections of the storage disks to determine whether the 1 MB slices to be accessed have been initialized to zero. Any 1 MB slices to be accessed that have not yet been initialized to zero are initialized to zero at the time of performing the write operations.